Investigators expect the SpO2 to remain stable over time. For assessing this, at least graphically, Functional data analysis (FDA) on all the full individual profiles will be performed. FDA creates a curve profile (via statistical penalized fitting of splines) for the SpO2 data with respect to time for each individual. Hence a mean profile or mean curve can be derived from all the subjects with their corresponding 95% confidence bands. This will be done separately for Day 0 and day 1, day 2, etc.